The shell of each new room is bullet-resistant and fire-retardant, and the rooms themselves could withstand a mortar attack and even possibly a direct hit by a small airplane, the newspaper said. Windsor Castle is on the flight path for London’s Heathrow Airport.

The rooms are equipped with secure communications, beds, washing facilities and enough food and hot water for the royals to survive at least a week.

The rooms were built following a security review after the Sept. 11, 2001, terror attacks in the U.S.

Tom Gaffney, owner of Gaffco, which manufactured the panic rooms and does a lot of business in New York City, said the rooms would be hidden from public view.

He added that security experts likely would advise the queen to take her beloved Welsh corgi dogs into the room with her in the event of an attack. “If you leave them outside, they’ll sniff you out and their barking would give you away,” he said.